Spin-dyeing of acrylonitrile polymers



United States Patent SPH I-BYElNG (3F AQRYLQNETRIILE vvinfried Kruclrenbcrg, Leverlrusen-Bayerwerir, and Adam Schultheiss, Dormagen, Germany, assignors to Fairbanfahriizen Bayer Alrtiengesellschatt, Leverirusen, Germany, a corporation of Ger'nany No Erawing. Filed Get. 17, 15 555, Ser. No. 767,771

Claims priority, application Germany Get. 18, E57

The present invention relates to the spin-dyeing of acrylonitrile polymers; more particularly it concerns a process wherein polyacrylonitrile or interpolyrners of acrylonitrile and other copolyrnerisable compounds containing at least 70% acrylonitrile are spin-dyed by means of basic dyestuffs which are soluble in the solvents used for the spinning, for instance in dimethyl forrnarnide, dirnethyl sulione, ethylene carbonate or nitro methane.

According to the present invention basic dyestuffs are used in the spin-dyeing of the acrylonitrile polymers which have been precipitated from their aqueous solutions.

These precipitated basic dyestuffs show a surprising increase of the solubility in the solutions serving for the spinning of the acrylonitrile polymers; with the aid of the precipitated basic dyestuffs, stock dyestuff solutions for=exarnple can be prepared for the spin dyeing which are made up with a significantly higher dyestufi content than hitherto possible. This applies particularly when dimethyl formarnide is used as solvent. Moreover, the basic dyestuffs to be used according to the invention in the spinning process no longer give rise to troubles such as were frequently to be observed in the use of the water soluble basic starting dyestuffs on account of frequently entrained water soluble foreign salts. It is also noteworthy that the spinning masses treated with the proposed basic dyestufis yield threads or fibres which possess a fastness to cross-dyeing which is better than that of threads or fibres obtainable from spinning masses which have been treated in the conventional manner with the corresponding water soluble dyestuffs. Contrary to most of the inorganic or organic pigments the basic dyestuffs which were precipitated from their aqueous solutions do not tend to clog the spinning nozzles; furthermore they do not bleed when the filaments are stretched in the precipitating bath.

To obtain the basic dyestuffs to be applied according to the invention one can for example proceed by dissolving the basic dyestuffs produced in a customary manner and which can belong to the most various seriese.g. the triphenyl-rnethane series, the anthraquinone series, the azo series, the rnethine series or Le phthalocyanine seriesin water and then adding sulionic acids or water soluble salts of sulfonic acids to the aqueous solutions. As suitable sulfonic acids, aliphatic acids and aromatic acids come into consideration such as, for example, propane-1,3-disulfonic acid, benzene rnonoor disultonic acid, naphthalene monoor polysulfonic acid, dipheny 4-sulfonic acid and condensation products of formaldehyde with naphthalene sultonic acid or with 4,4-dihydroxy diphenyl sulphone containing sultonic acid groups. Instead of the sulfonic acids or their salts also other acids, such as rnaleic acid, fumaric acid, adipic acid, citric acid, trichloro acetic acid, boroiluoro actic acid, borofluoro butyric acid and hydrofiuoboric acid or their water soluble salts may be used for precipitation. As water soluble salts the alkali metal salts are especially suitable.

The precipitation of the basic dyestuffs with the acids or their water soluble salts from the aqueous solutions can be effected in the cold or also with warming, the most suitable temperature being readily determinable in each case by preliminary experiments. The suitable proportions of the components can also be etermined by prelirniriary experiments without difliculty; in general it is recommended to-apply the acids or their salts in a slight excess in relation to stoichiometric quantity.

The basic dyestuffs to be used according to the inven- 5 tion for spin dyeing acrylonitrile polymers include also those basic dyestufis of the azo series which are precipitated by adding the acids or their salts which come into consideration already during the production of the azo dyestuffs, for instance during coupling, instead of after the production of the azo dyestufif.

The dyestuffs in the present case can, as is customary, be introduced into the spinning masses in the form of stock solutions; stock solutions made up with dimethyl fcrrnarnide can contain for example 15-20% acrylonitrile polymer and -30% dyestuff.

Example 1 or of the formula 5 were dissolved in 750 ml. of water at 55 C. There was then added with good stirring within 15 minutes 150 g. of a 40% aqueous solution of the sodium salt of the condensation product of formaldehyde with 4,4'-dihydroxy diphenyl sulfone containing sulfonic acid groups. The reaction m xture was further stirred for half an hour and then cooled to 2025 C. T e precipitated red dyestuir" was filtered off with suction, washed with water and dried. For the precipitation of the dyestuffs 120 g. of a aqueous solution of sodium propane-1,3,-disulfonate or 40 ml. of borofluoro acetic acid or 40 ml. of hydrofiuoboric acid (13 01.22) can be used instead of 150 g. of the 48% aqueous solution of the condensation product.

Example 2 The procedure described in Example 1 is followed but instead of the bale dyestuffs used for the spin dyeing, a basic dyestuff is applied which has been precipitated by adding 190 ml. of the 40% solution of the condensation product of Example 1 at 55 C. to an aqueous solution of g. of the yellow dyestuff of the formula is treated, instead of with the 40% aqueous solution of the condensation product of Example 1, with a 40% aque- 3 one solution of the condensation product of formaldehyde and sodium naphthalene sulfonate or sodium naphthalene 1,5-disu1fonate.

Example 3 The procedure of Example 1 is followed, but instead of the dyestuffs used, the basic dyestufi is applied which precipitates if a solution of 20 g. of the orange coloured dyestufr of the formula is treated at 55 C. with 50 ml. of the 40% aqueous solution of the condensation product applied in Example 1.

Example 4 The procedure described in Example 1 is followed but instead of the dyestuifs described the basic dyestufi is used which precipitates if at 55 C. the aqueous solution of 20 g. of the blue-black dyestuff of the formula is treated with an aqueous solution of 15 g. of sodium naphthalene-l,5-disulfonate or 15 g. of sodium diphenyl- 4-sulfonate.

Example 5 The procedure of Example 1 is followed but instead of the dyestuffs described, the basic dyestuff is used which precipitates if a solution of 60 g. of the violet dyestuif of the formula is treated in 700 ml. of water at 80 C. as described in Example 1 with 75 ml. of the 40% aqueous solution of the condensation product indicated in Example 1.

Example 6 For the sp n dyeing as described in Example 1 a basic dyestutf is used which has been obtained in the following way:

To 450 ml. of 30% hydrochloric acid, 100 g. of 2- amino-S-chloro-benzo-trifiuoride are added dropwise with stirring in the course of 1 /2 to 2 hours. The mixture is then further stirred for several hours and then cooled by external cooling to a temperature below 0 C. A solution of 36 g. of sodium nitrite in 70 ml. of water is thereupon added dropwise within two hours, care being taken that the temperature does not rise above 0 C. After the reaction mixture has been stirred for a further 30 minutes it is filtered. The slight excess of nitrite in the filtrate is removed with amido sulfonic acid and the diazo solution is then poured into a solution prepared by dissolving 100 g. of naphthalene-1,S-disulfonic acid and 160 g. of N-ethyl-N-phenyl-B-amino-ethyl-trimethyl-ammonium chloride in 600 ml. of Water. The mixture is partially neutralized, with further addition of ice, with concentrated caustic soda to a pH of 5.5 to 6.5 and stirred for another hour. The dyestufi which has meanwhile separated out is then filtered ofi with suction, Washed free from salt with water and dried at 50-60 C.

4. Example 7 The procedure described in Example 1 is followed using a basic dyestuii: obtained in the following way:

50 g. of the blue dyestufif of the formula are dissolved in 300 ml. water with the addition of 10 ml. of glacial acetic acid at 6070 C. and this solution is added to another solution of 35 g. of sodium-a-naphthalene sulionate in 200 ml. of water and containing 250 g. of ice. The precipitated dyestufi is then filtered oil and dried.

Example 8 The procedure described in Example 1 is followed but instead of the basic dyestuffs used for the spin dyeing, a basic dyestulf is applied which was precipitated by treating an aqueous solution of 36 g. of the dyestutf of the formula with an aqueous solution of 33 g. of naphthalene-1,5- disulfonic acid sodium salt.

Example 9 The procedure described in Example 1 is followed but instead of the basic dyestufis used for the spin dyeing, a basic dyestuif is applied which has been precipitated in the following manner:

40 g. or the dyestuii of the formula oH31 IC H:

are dissolved in 300 ml. of water and to the aqueous solution there is added a solution of 26 g. of sodium citrate in m1. of water or a solution of 22.5 g. of sodium maleate in 20 ml. of water. After cooling the mixture to 20 C. the precipitated basic dyestutt is filtered off with suction, washed with Water and dried at 50-60 in vacuo.

We claim:

1. In the process of spin-dyeing acrylonitrile polymers with basic dyestufis which are soluble in the solvent used for the spinning, the step which comprises using basic dyestuffs which have been precipitated from their aqueous solution by means of a member selected from the group consisting of an aromatic sulfonic acid and a water soluble salt of an aromatic sulfonic acid, said member having at least 2 aromatic rings.

2. The process of claim 1 wherein the member is the References Cited in the file of this patent sodium sulfonate of the condensation product of formaldehyde with 4,4'-dihydroxy diphenyl sulfone. UNITED STATES PATENTS 3. The process of claim 1 wherein the member is 2,811,515 stfmker 1957 the condensation product of formaldehyde and sodium 2,875,211 Selbert et a1 1959 naphthalene sulfonate. 5 2,906,588 Bnlrlkhorst et a1 Sept. 29, 1959 4. The process of claim 1 wherein the member is 2,941,970 Cralg June 1950 sodium naphthalene 1,5-disu1f0nate. FOREIGN PATENTS 5. The process of claim 1 wherein the member is 616,440 Great Britaln Jan. 21, 1949 30mm dphenyl'4'sulfnate 10 686,269 Great Britain Ian. 21, 1953 6. The process of claim 1 wherein the member is sodium-u-naphthalene sulfonate. OTHER REFERENCES Fierz-David and Blangey: Fundamental Processes of Dye Chemistry, Interscience Pub. Inc., New York, 1949. 

1. IN THE PROCESS OF SPIN-DYEING ACRYLONITRILE POLYMERS WITH BASIC DYESTUFFS WHICH ARE SOLUBLE IN THE SOLVENT USED FOR THE SPINNING, THE STEP WHICH COMPRISES USING BASIC DYESTUFFS WHICH HAVE BEEN PRECIPITATED FROM THEIR AQUEOUS SOLUTION BY MEANS OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF AN AROMATIC SULFONIC ACID AND A WATER SOLUBLE SALT OF AN AROMATIC SULFONIC ACID, SAID MEMBER HAVING AT LEAST 2 AROMATIC RINGS. 